title: Reference values for anxiety questionnaires: the Leiden Routine Outcome Monitoring Study.
abstract: BACKGROUND
  The monitoring of patients with an anxiety disorder can benefit from Routine Outcome Monitoring (ROM). As anxiety disorders differ in phenomenology, several anxiety questionnaires are included in ROM: Brief Scale for Anxiety (BSA), PADUA Inventory Revised (PI-R), Panic Appraisal Inventory (PAI), Penn State Worry Questionnaire (PSWQ), Worry Domains Questionnaire (WDQ), Social Interaction, Anxiety Scale (SIAS), Social Phobia Scale (SPS), and the Impact of Event Scale-Revised (IES-R). We aimed to generate reference values for both 'healthy' and 'clinically anxious' populations for these anxiety questionnaires.
  
  
  METHODS
  We included 1295 subjects from the general population (ROM reference-group) and 5066 psychiatric outpatients diagnosed with a specific anxiety disorder (ROM patient-group). The MINI was used as diagnostic device in both the ROM reference group and the ROM patient group. To define limits for one-sided reference intervals (95th percentile; P95) the outermost 5% of observations were used. Receiver Operating Characteristics (ROC) analyses were used to yield alternative cut-off values for the anxiety questionnaires.
  
  
  RESULTS
  For the ROM reference-group the mean age was 40.3 years (SD=12.6), and for the ROM patient-group it was 36.5 years (SD=11.9). Females constituted 62.8% of the reference-group and 64.4% of the patient-group. P95 ROM reference group cut-off values for reference versus clinically anxious populations were 11 for the BSA, 43 for the PI-R, 37 for the PAI Anticipated Panic, 47 for the PAI Perceived Consequences, 65 for the PAI Perceived Self-efficacy, 66 for the PSWQ, 74 for the WDQ, 32 for the SIAS, 19 for the SPS, and 36 for IES-R. ROC analyses yielded slightly lower reference values. The discriminative power of all eight anxiety questionnaires was very high.
  
  
  CONCLUSIONS
  Substantial non-response and limited generalizability.
  
  
  CONCLUSIONS
  For eight anxiety questionnaires a comprehensive set of reference values was provided. Reference values were generally higher in women than in men, implying the use of gender-specific cut-off values. Each instrument can be offered to every patient with MAS disorders to make responsible decisions about continuing, changing or terminating therapy.
authors.affiliation: Department of Psychiatry, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands. Y.W.M.Schulte-van_Maaren@lumc.nl
authors.forename: Yvonne W M
authors.initials: YW
authors.lastname: Schulte-van Maaren
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Giltay
authors.forename: Albert M
authors.initials: AM
authors.lastname: van Hemert
authors.forename: Frans G
authors.initials: FG
authors.lastname: Zitman
authors.forename: Margot W M
authors.initials: MW
authors.lastname: de Waal
authors.forename: Ingrid V E
authors.initials: IV
authors.lastname: Carlier
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D017063:Outcome Assessment, Health Care; D010045:Outpatients; D010200:Panic; D010549:Personal Satisfaction; D010555:Personality Inventory / Q000706:statistics & numerical data; D010698:Phobic Disorders / Q000175:diagnosis / Q000523:psychology; D012372:ROC Curve; D012016:Reference Values; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult
keywords: Anxiety; Anxiety disorders; Instruments; Questionnaires; Reference values; Routine Outcome Monitoring